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http://hdl.handle.net/11375/27974
Title: | SYNTHESIS OF ANTIFOULING, BIOFUNCTIONAL “ROMANTIC” POLYMER COATINGS |
Authors: | Jesmer, Alexander |
Advisor: | Wylie, Ryan |
Department: | Chemical Biology |
Keywords: | Biomaterials, polymers, antifouling, biosensors, LSPR, elastomers, |
Publication Date: | 2022 |
Abstract: | Materials in contact with the biological milieu (biomaterials) spontaneously and nonspecifically adsorb constituent proteins which may lead to unwanted cell adhesion and responses or hinder device performance. These interactions and their related phenomena lead to complications in ~3% of implant surgeries. Thus, resistance to these nonspecific interactions is critical to the performance of many implanted biomaterials and biosensing surfaces. Further, these interactions have widespread importance to industrial materials in contact with biological environments such as food packaging, and agricultural and nautical surfaces. Thin film coatings of antifouling polymers are one of the leading methods for reducing nonspecific interactions. Both polymer composition (chemical composition and molecular weight) and polymer grafting density are the principal determinants of coating performance. For applications requiring specific bioactivity, such as selective ligand-analyte interactions for sensors, the polymer coating must remain antifouling and be amenable to functionalization with capture ligands. Tethered polymer coatings can be made by surface initiated polymerization (“graft-from”) which results in higher density coatings, but complex fabrication limits commercialization and capacity of functionalization with capture ligands. Simpler “graft-to” procedures, where pre synthesized polymers are immobilized to a surface, are more amenable to translation but suffer from inferior antifouling properties due to lower density coatings. New fabrication methods are therefore required to improve both graft-to and graft-from coatings. Herein, the effects of polymer density on material performance are explored and leveraged to produce novel functional surfaces using two classes of polymers, namely amphiphilic and thermoresponsive poly(oligo(ethylene glycol)) methyl ether methacrylate, and zwitterionic, functionalizable poly(carboxybetaine methacrylamide) (pCB), as well as copolymers thereof. Specifically, polymer grafting techniques which exploit grafting density effects on surfaces were developed, leading to surfaces: 1) that are both high-loading and antifouling due to two different grafting densities within bimodal architectures, and (2) with enhanced anti-fouling properties despite being prepared via a “grafting-to” method using shrinkable or expandable substrates. Interestingly, shrinking substrates with antifouling polymers resulted in a novel LSPR biosensor with high translation potential. Chapter 2 describes the pH controlled, one-pot production of two-layer brushes composed of an antifouling dense layer and a high-loading lower density layer where capture ligand immobilization was improved by 6 times compared to a single high density layer. Towards improving fouling and bioactivity of graft-to surfaces, Chapter 3 describes the first demonstration of Graft-then-Shrink where a stretched polystyrene (PS) substrate coated in a thin gold layer modified with thiol-terminated pCB was thermo-shrunk to one sixth in footprint to increase polymer surface coating content for enhanced antifouling properties and the production of micro/nano gold wrinkles to generate a localized surface plasmon resonance (LSPR) active surface. The low-cost sensors can vi detect biomolecular interactions by tracking changes in absorbance in the visible spectrum using ubiquitous plate readers. In Chapter 4, Graft-then-Shrink was extended to elastomeric materials, where thiol terminated polymers were grafted onto solvent swollen silicone via thiol-maleimide click chemistry, producing strongly antifouling materials. Taken together, these developments represent significant advances in the preparation and application of antifouling polymer coatings towards the improvement of antifouling surface properties of medical devices and resulted in the development of a novel, low-cost LSPR sensor without the need for specialized equipment. |
URI: | http://hdl.handle.net/11375/27974 |
Appears in Collections: | Open Access Dissertations and Theses |
Files in This Item:
File | Description | Size | Format | |
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Jesmer_Alexander_H_202209_PhD.pdf | 17.25 MB | Adobe PDF | View/Open |
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